Snapchat has reigned supreme as teens’ favorite social platform for a couple of years now, according to Piper Jaffray’s semi-annual teen surveys. But Snapchat’s rise may be cooling off, and Instagram may be seeing renewed interest from teens, per the latest results.

Asked their favorite social media platform, almost half (46%) of the 8,600 teens surveyed for the report cited Snapchat. That was squarely in the range set in the past 2 surveys, when similar proportions of teens pointed to Snapchat as their favorite platform.

What’s different about this latest edition of the survey is the uptick in popularity for Instagram. Almost one-third (32%) reported that Instagram is their favorite platform, up from 26% in the previous survey, and reaching the highest level in at least 3 years.

It’s important to note that Instagram’s rising influence isn’t coming at the expense of Snapchat, but rather Facebook and Twitter. For example, just 5% of teens named Facebook their favorite social media platform, down from 8% in the previous survey. And Twitter didn’t fare much better, with its 6% share of the vote being down from 9% in the previous study.

Still, it’s notable that Instagram is the one taking the place of those other social platforms, rather than Snapchat. If those trends were to hold, Instagram could rise to challenge Snapchat as teens’ favorite social platform overall in a true two-horse race. Consider that Snapchat and Instagram combined were cited as the favorite platform of 78% of teens, the highest share of vote for the top two platforms in several years.

Instagram and Snapchat Neck-and-Neck in Overall Usage

One result that’s also in Instagram’s favor: it’s now the most-used social platform among the teens surveyed. After being virtually tied for several quarters, Instagram has edged ahead in this latest report, with 85% of respondents using the platform at least once per month.

Still, 84% of teens use Snapchat with that regularity, so they are essentially tied, as the 1% point difference is almost assuredly within the survey’s margin of error.

Meanwhile, Facebook continues its drastic decline. Only 36% of teens surveyed reported using Facebook at least once per month, down from 45% just 6 months earlier. For comparison, just 2-and-a-half years ago, 60% of teens were using Facebook on a monthly basis. And in this latest study only 28% of 15-year-olds said they’re on Facebook at least monthly.

Twitter is also falling out of popularity: fewer than half (47%) of teens said they use Twitter at least once a month, the first time it has dropped below majority usage in some time.

Snapchat Improves As A Marketing Channel, Though

Although Instagram has been gaining momentum, Snapchat does have one encouraging result: teens are starting to see it more as a brand engagement vehicle than in the past.

In this survey Snapchat rivaled email as the second-best way for a retailer or brand to communicate with teens about new products or promotions.

Of course, the best marketing channel, as told by teens? Instagram, again. This is supported by other recent research in which Snapchat was preferred by Gen Z for posting videos and selfies, but Instagram topped the list for following brands.

About the Data: The results are based on a survey of 8,600 teens across 47 U.S. states with an average age of 15.9. Some 56% of respondents are male, and the sample has an average household income of $68,300.